Namespace all wpilibc functions/classes into "frc" namespace. (#311)

Base.h provides a backwards compatibility shim (enabled unless
NAMESPACED_WPILIB is defined) that does a "using namespace frc".
However, as some header files do not include Base.h, this may
be a breaking change in some corner cases (with an easy fix).

Fixes #218.

wpilibc/athena/include/PowerDistributionPanel.h

@@ -13,6 +13,8 @@
 #include "LiveWindow/LiveWindowSendable.h"
 #include "SensorBase.h"
 
+namespace frc {
+
 /**
  * Class for getting voltage, current, temperature, power and energy from the
  * CAN PDP.
@@ -42,3 +44,5 @@ class PowerDistributionPanel : public SensorBase, public LiveWindowSendable {
   std::shared_ptr<ITable> m_table;
   int m_module;
 };
+
+}  // namespace frc